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From: Robert A Duff <bobduff@shell01.TheWorld.com>
Newsgroups: comp.lang.ada
Subject: Re: Initialization and Finalization of limited object "returned" by a
  function
Date: Fri, 12 Feb 2010 14:11:54 -0500
Organization: The World Public Access UNIX, Brookline, MA
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Date: 2010-02-12T14:11:54-05:00
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Adam Beneschan <adam@irvine.com> writes:

> But, assuming that there are no controlled components, there's nothing
> preventing the compiler from generating the same code for Func1 as for
> Func2, and eliminating the extra copy.  So I guess that using extended
> return might be worth a try---try it both ways, and see if the
> compiler generates faster code.
>
> If there are controlled components, then the semantics are different,
> because Func1 will have to assign Result to the "result
> object" (requiring an "adjust" operation) and then finalize Result
> (requiring a "finalize" operation).  The language gives compilers
> permission to remove adjust/finalize pairs in some cases, but I don't
> know if this is one of those cases.

I think it is.  But I'm too lazy to look it up right now.

If I'm right, then compilers can optimize in both
controlled and non-controlled cases (for nonlimited
types).

>...If not, then this is a case where
> extended return will definitely benefit you.

- Bob